Strategies used by soil biota to overcome soil organic matter stability - why is dead organic matter left over in the soil?
Strategies used by soil biota to overcome soil organic matter stability - why is dead organic matter left over in the soil?
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DOI：
10.1016/j.geoderma.2004.12.024
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发表时间：
2005-09-01
期刊：
影响因子：
6.1
通讯作者：
Wolters, V
中科院分区：
文献类型：
--
作者：
Ekschmitt, K;Liu, MQ;Wolters, V
为了更好地了解石油有机质稳定性的条件性质，我们提出了一个概述（1）生物策略和（2）生态过程，分解有机体获得或阻止代谢土壤有机资源。讨论的生物策略包括众所周知的活动，如胞外酶的释放，有机残留物的机械破碎，土壤质量的生物扰动，以及在活生物量中固定碳。所描述的生态过程在延长土壤有机质的持久性方面的重要性受到的关注较少。模型计算表明，细胞能量消耗迫使微生物以低分解率运行，扩散损失抑制微生物生长并阻碍新微生物菌落的形成。分解生物对特定微生境和基质的专门化导致暂时无法获得有机资源的避难所。我们得到四个稳定性标准，我们分类有机质池：被动与主动稳定，部分与绝对避难所。两个案例研究证实，在温带土壤中占主导地位的数量的有机物质居住在被动稳定/部分避难所的状态，并持续存在，尽管是可访问和可分解的。我们的结论是，土壤有机质是稳定的一个复杂的机制，限制分解率，其中几个不是基于基质质量或土壤条件，但对生物学的分解土壤生物。(c)2004 Elsevier B. V.保留所有权利。
Aiming at an improved understanding of the conditional nature of,oil organic matter stability, we present an overview of (1) biotic strategies and (2) ecological processes by which decomposer organisms gain access to, or are prevented from metabolising soil organic resources. The biotic strategies discussed comprise well-known activities, such as the release of exo-enzymes, the mechanical crushing of organic residues, the bioturbation of soil mass, and the fixation of carbon in the living biomass. The ecological processes described have received less attention regarding their importance in prolonging the persistence of soil organic matter. Model calculations illustrate that cell energy de-land forces micro-organisms to operate at low decomposition rates, and that diffusion losses inhibit microbial growth and impede the formation of new microbial colonies. The specialisation of decomposer organisms towards particular microhabitats and substrates gives rise to refuges where organic resources are temporarily not accessed. We derive four stability criteria, by which we classify organic matter pools: passive versus active stabilisation, and partial versus absolute refuge. Two case studies confirm that in temperate soils a dominant quantity of organic material resides in the passive stabilisation/partial refuge status and persists in spite of being accessible and decomposable. We conclude that soil organic matter is stabilised by a complex of mechanisms that constrain decomposition rates, several of which are not based on substrate quality or soil conditions, but on the biology of the decomposing soil organisms. (c) 2004 Elsevier B.V. All rights reserved.